Nitrogen management in rice transplanted with aged seedlings

Different N management strategies involving the use of leaf colour chart (critical value 4), were evaluated to refine the technique of the use of (LCC) in assessing the N requirement of rice in contingencies when aged seedlings were used for transplanting. Rice variety ADT 46 during Navarai and ADT 43 during wet season were tried as the test crops. The results indicated that basal application of 35 kg N ha−1 is necessary to avoid the yield loss (6.5 -14.9%) in rice when more than 35 days old aged seedlings were used for transplanting. Use of 45 days old seedlings had resulted in a marked reduction in the productive tillers (9.1 to 15.7%) in rice under the LCC based N management where the crop did not receive any basal N. Skipping the basal N for aged seedlings had also increased the percentage of unproductive tillers and inturn decreased the grain yield. A marked reduction (11.3–14.6 per cent) in the N uptake in rice under the LCC based N management was observed when the age of the seedlings exceeded 35 days and the same could be improved by the basal application of N.